The present invention relates to a drive assembly, particularly for driving a vehicle, having a driving engine and an auxiliary engine as well as auxiliary assemblies driven by way of a clutch selectively by one of the engines.
French Patent Document FR-A-1 463 799 shows a drive assembly with a driving engine to which an auxiliary engine is assigned for the optional driving of auxiliary assemblies. The auxiliary engine which, if required, is used for driving the auxiliary assemblies is arranged laterally of the driving engine. The auxiliary assemblies are arranged at a distance from the clear frontal areas of both engines and constructionally are assigned essentially to the auxiliary engine. The considerable installation space is a disadvantage in this case.
The present invention is based on the object of providing, for a drive assembly, an arrangement of an auxiliary engine with a lower requirement with respect to installation space.
This object has been achieved according to the present invention in that a single-bank radial engine constructed as an internal-combustion engine is arranged as an auxiliary engine in a clear frontal area of the driving engine. Furthermore, a particularly space-saving arrangement is achieved by a single-bank radial engine which is constructed as a 4-cylinder 2-stroke engine with a crank guide power unit. By virtue of this single-bank radial engine which is described in detail, for example, in the European Patent EP-A-0 187 930, a short, compact and powerful auxiliary engine is achieved for a space-saving arrangement. However, the present invention is advantageous not only with respect to the overall size of the auxiliary engine. It also represents a considerable advantage with respect to the overall arrangement because of the fact that auxiliary assemblies may remain which are provided in the front-side end area of the driving engine and are arranged in order to utilize the given installation space. Thus, a separate arrangement which requires additional installation space is unnecessary.
The advantageous arrangement of the present invention is promoted in a simple manner in that the single-bank radial engine with the interposition of a shiftable clutch is arranged in alignment with a power unit shaft of the driving unit.
A further feature of the present invention achieves short overall length of the drive assembly in that, on the outer circumference, the clutch is in a rotating connection with output pulleys of enveloping gears provided in several planes in the clear frontal area of the driving engine for driving the auxiliary assemblies.
The above-described shiftable clutch may be configured such that by means of it, the auxiliary assemblies are optionally driven by the single-bank radial engine during stoppage, idling or possibly heavy loading of the driving engine. However, an operating method is also conceivable for the shiftable clutch in that, if required, only some of the auxiliary assemblies are driven by the single-bank radial engine. This applies particularly to the case in which one or several of these separately optionally driven auxiliary assemblies have to furnish an increased power which cannot be provided when the given rotational speed of the driving engine is maintained, such as an increased air-conditioning performance and/or an increased electric consumption from the wiring at a slow driving speed or a stop-and-go driving method of the vehicle.
In addition, the single-bank radial engine and the shiftable clutch can form a retrofit unit.